Project services

Integration with services such as Campfire, Flowdock, Gemnasium, HipChat,
Pivotal Tracker, and Slack are available in the form of a Project Service.

SSL certificate errors

When trying to integrate GitLab with services that are using self-signed certificates,
it is very likely that SSL certificate errors will occur on different parts of the
application, most likely Sidekiq. There are 2 approaches you can take to solve this:

Add the root certificate to the trusted chain of the OS.

If using Omnibus, you can add the certificate to GitLab's trusted certificates.

OS main trusted chain

This resource
has all the information you need to add a certificate to the main trusted chain.